Climate change is adversely affecting sea turtles

Swansea
-
Sea turtles are endangered animals, with the global population in decline. Risks include hunting, for turtle eggs and skin, and now, based on new research, from climate change.

The new study highlights the dangers of climate change for the turtles and a risk model indicates how, without appropriate action, climatic events could lead to the extinction of the species. The findings are based on a six yearlong study of sand temperatures and titles at the Cape Verde islands. The overall outcome showed how warming temperatures are impacting upon turtle populations.

Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles belonging to several species: the green, loggerhead, Kemp's ridley, olive ridley, hawksbill, flatback, and leatherback. Sea turtles are temperature-dependent sex determination type species. This means that the external temperature has a significant impact on determining whether embryo becomes a male or female before birth. The important cut-off is 29º C (84.2º F). Should the temperature go higher this typically means the embryo is more likely to lean female; whereas cooler temperatures are more likely to lead to a male.

Thus a rise in temperatures is leading to a disproportionate number of females and too few males, according to the British research. This is adversely affecting on the ability of the turtles to reproduce. There’s a further concern with rising temperatures. Where temperatures edge over 35º C, this is too hot for embryos to develop leading to a loss of fertility.

Discussing this in a research note, Dr Jacques-Oliver Laloë (Department of Biosciences, Swansea University, Swansea, U.K.), who led the study says: “In recent years, in places like Florida—another important sea turtle nesting site—more and more turtle nests are reported to have lower survival rates than in the past.”

The consequence of this, he adds, “shows that we should really keep a close eye on incubation temperatures and the in-nest survival rates of sea turtles if we want to successfully protect them.”

The figures collated by Dr. Laloë indicate that by the year 2100 sea turtles could become extinct. To avoid this, conservation measures are needed to protect incubating turtle eggs, such as building artificially shade areas or moving eggs to a protected hatchery.

The research is published in the journal Global Change Biology. The research paper is titled “Climate change and temperature-linked hatchling mortality at a globally important sea turtle nesting site.”